Information security has become a major cause of concern because intruders are concerned with reading the information. It is because of electronic dropping security is under threat. This paper deals with the comparative analysis of steganography over coloured images. �Steganography� is a greek word which means �hidden writing�. It is the art of hiding the secret message within a image. The goal of steganography is to avoid drawing suspicious to transmission of hidden message. It serves a better way of securing message than cryptography which provide security to content of message and not the existence. Original message is being hidden within a carrier such that the changes occurred in carrier are not observed. The hidden message in carrier is difficult to detect without retrieval. Different techniques are described in this paper for steganography over coloured images. One of them is spatial steganography. In this technique some bits in the image pixel is used for hiding data. Second technique is Transform Domain Technique which is a more complex way of hiding information in an image. Using Distortion technique, a stego object is created by applying a sequence of modifications to the cover image. The message is encoded at pseudo-randomly chosen pixels. Masking and Filtering technique embed the information in the more significant areas than just hiding it into the noise level. The hidden message is more integral to the cover image. Steganography is efficient, simple and decreases the degree of attack on secret information and improve image quality.

Steganography, Cryptography, Secret Information, Distortion, Spatial, Tranform Domain, Masking and Filtering

[1] R.Amirtharajan and R.John Bosco Balaguru. ―Constructive Role of SFC& RGB Fusion versus Destructive Intrusion‖.Proc. International Journal of Computer Applications1(20):30�36
[2] W. Bender, D. Gruhl, N. Morimoto, A. Lu, ―Techniques for data hiding. Proc. IBM Syst. J. 35 (3&4) (1996) 313�336.
[3] N. Provos and P. Honeyman, ―Hide and seek: An introduction to steganography, Proc. IEEE Security Privacy Mag.,1 (3) (2003) 32�44
[4] Sutaone, M.S., Khandare, M.V, �Image based steganography using LSB insertion technique�, Proc. IEEE WMMN, pp. 146-151, January 2008.
[5] Shareza Shirali, M.H, �Anew Approach to persain/Arabic Text Steganography�, Computer and Information Science, 2006, ICISCOMSAR 2006,Proc. 5th IEEE/ACIS International Conference, 10- 12 July 2006 pp 310-315.
[6]R.Amirtharajan and Dr. R. John Bosco Balaguru, ―Tri-Layer Stego forEnhanced Security � A Keyless Random Approach‖ - IEEE Xplore, DOI, 10.1109/IMSAA.2009.5439438.
[7] F.A.P. Petitcolas, R.J. Anderson, and M.G. Kuhn, �Information Hiding�A Survey,� Proc. IEEE, vol. 87, no. 7, 1999, pp. 1062�1078.
[8] Jamil, T., �Steganography: The art of hiding information is plain sight�,ProcIEEE Potentials, 18:01, 1999.
[9] Jagvinder Kaur and Sanjeev Kumar, � Study and Analysis of Various Image Steganography Techniques�Proc. IJCST Vol. 2, Issue 3, September 2011 [10] R.Amirtharajan and R. Akila,� A Comparative Analysis of Image Steganography;� Proc. International Journal of Computer Applications (0975 � 8887) ,Volume 2 � No.3, May 2010.
[11]Video Steganography by LSB Substitution Using Different Polynomial Equations‖, A. Swathi, Dr. S.A.K Jilani, Proc.International Journal of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5 [12]Chandramouli, R., Kharrazi, M. & Memon, N., �Image steganography and steganalysis: Concepts and Practice�, Proceedings of the 2 ndInternational Workshop on DigitalWatermarking, October 2003.
[13]Moerland, T., �Steganography and Steganalysis�, Leiden Institute of AdvancedComputing Science,www.liacs.nl/home/tmoerl/privtech.pdf